From fb3012448d773e657c88f06fa7398e388db64cff Mon Sep 17 00:00:00 2001
From: milarin <milaring@proton.me>
Date: Mon, 10 Jul 2023 17:16:51 +0200
Subject: [PATCH] ring implemented

---
 impl_ring_array.go       | 13 ++++++++
 impl_ring_linked_list.go | 13 ++++++++
 impl_ring_list.go        | 65 ++++++++++++++++++++++++++++++++++++++++
 int_ring.go              | 13 ++++++++
 utils.go                 | 15 ++++++++++
 5 files changed, 119 insertions(+)
 create mode 100644 impl_ring_array.go
 create mode 100644 impl_ring_linked_list.go
 create mode 100644 impl_ring_list.go
 create mode 100644 int_ring.go
 create mode 100644 utils.go

diff --git a/impl_ring_array.go b/impl_ring_array.go
new file mode 100644
index 0000000..a4fe534
--- /dev/null
+++ b/impl_ring_array.go
@@ -0,0 +1,13 @@
+package ds
+
+type ArrayRing[T any] struct {
+	*ListRing[T, *ArrayList[*T]]
+}
+
+var _ Ring[int] = &ArrayRing[int]{}
+
+func NewArrayRing[T any](size int) *ArrayRing[T] {
+	return &ArrayRing[T]{
+		ListRing: NewListRing[T](NewArrayList[*T](size), size),
+	}
+}
diff --git a/impl_ring_linked_list.go b/impl_ring_linked_list.go
new file mode 100644
index 0000000..a8f74fe
--- /dev/null
+++ b/impl_ring_linked_list.go
@@ -0,0 +1,13 @@
+package ds
+
+type LinkedListRing[T any] struct {
+	*ListRing[T, *LinkedList[*T]]
+}
+
+var _ Ring[int] = &LinkedListRing[int]{}
+
+func NewLinkedListRing[T any](size int) *LinkedListRing[T] {
+	return &LinkedListRing[T]{
+		ListRing: NewListRing[T](NewLinkedList[*T](), size),
+	}
+}
diff --git a/impl_ring_list.go b/impl_ring_list.go
new file mode 100644
index 0000000..a0e84c5
--- /dev/null
+++ b/impl_ring_list.go
@@ -0,0 +1,65 @@
+package ds
+
+type ListRing[T any, L List[*T]] struct {
+	list    L
+	current int
+}
+
+var _ Ring[int] = &ListRing[int, List[*int]]{}
+
+func NewListRing[T any, L List[*T]](list L, size int) *ListRing[T, L] {
+	preAllocList[*T, List[*T]](list, nil, size)
+	return &ListRing[T, L]{
+		list:    list,
+		current: 0,
+	}
+}
+
+func (r *ListRing[T, L]) Next() Ring[T] {
+	return &ListRing[T, L]{
+		list:    r.list,
+		current: modAbs(r.current+1, r.list.Size()),
+	}
+}
+
+func (r *ListRing[T, L]) Prev() Ring[T] {
+	return &ListRing[T, L]{
+		list:    r.list,
+		current: modAbs(r.current-1, r.list.Size()),
+	}
+}
+
+func (r *ListRing[T, L]) Set(v T) {
+	r.list.Set(r.current, &v)
+}
+
+func (r *ListRing[T, L]) Has() bool {
+	return r.list.Get(r.current) != nil
+}
+
+func (r *ListRing[T, L]) Get() (T, bool) {
+	if !r.Has() {
+		return *new(T), false
+	}
+	return *r.list.Get(r.current), true
+}
+
+func (r *ListRing[T, L]) GetOrDefault(defaultValue T) T {
+	value, ok := r.Get()
+	if !ok {
+		return defaultValue
+	}
+	return value
+}
+
+func (r *ListRing[T, L]) Each(f func(value *T)) {
+	var t Ring[T] = r
+	for i := 0; i < r.list.Size(); i++ {
+		if value, ok := t.Get(); ok {
+			f(&value)
+		} else {
+			f(nil)
+		}
+		t = t.Next()
+	}
+}
diff --git a/int_ring.go b/int_ring.go
new file mode 100644
index 0000000..e3f8593
--- /dev/null
+++ b/int_ring.go
@@ -0,0 +1,13 @@
+package ds
+
+type Ring[T any] interface {
+	Iterable[*T]
+
+	Next() Ring[T]
+	Prev() Ring[T]
+
+	Set(T)
+	Has() bool
+	Get() (T, bool)
+	GetOrDefault(defaultValue T) T
+}
diff --git a/utils.go b/utils.go
new file mode 100644
index 0000000..d0db53d
--- /dev/null
+++ b/utils.go
@@ -0,0 +1,15 @@
+package ds
+
+func modAbs(a, b int) int {
+	v := a % b
+	if v < 0 {
+		return b + v
+	}
+	return v
+}
+
+func preAllocList[T any, L List[T]](list L, value T, size int) {
+	for list.Size() < size {
+		list.Add(value)
+	}
+}